[Bug][DataProxy] Adjust the fields statistics unit in DataProxyMetricItemSet

[gosonzhang]

What happened

The parent issue is:#5888

In the DataProxyMetricItemSet object, the units of the fields readSuccessCount, readFailCount, sendCount, sendSuccessCount, and sendFailCount are the number of message items[1], not the number of packets. The current implementation is based on the number of packets[2], which needs to be aligned.

1. https://inlong.apache.org/docs/next/modules/dataproxy/overview/
   

2. https://github.com/apache/inlong/blob/master/inlong-dataproxy/dataproxy-source/src/main/java/org/apache/inlong/dataproxy/metrics/DataProxyMetricItemSet.java#L137
   

What you expected to happen

the count of message items, not packages

How to reproduce

run and test

Environment

Linux

InLong version

master

InLong Component

InLong DataProxy

Are you willing to submit PR?

• Yes, I am willing to submit a PR!

Code of Conduct

• I agree to follow this project's Code of Conduct